Circuit breaker with magnetic device releasable to effect opening of the breaker



J1me 6 F. 0. JOHNSON 3,450,955

CIRCUIT BREAKER WITH MAGNETIC DEVICE R-ELEASABLE TO EFFECT OPENING OFTHE BREAKER Original Filed on. 29, 1964 Sheet of s 8 o 8 5 '55 I7 I? s,n49 *1 I47 1 r N 5 I s 5 I63 le. 27 I45 D.c. SOURCE 2 M3 Fi 5B. Flg .5AA r X X D D .J .J LL LL 0 H MMF 0 H MMF SOFT PERMANENT IRON MAGNETFig.4.

H9 nc. SOURCE INVENTOR Floyd 0. Johnson ATTORNEY June 17, 1969 F. D.JOHNSON 3,450,955

CIRCUIT BREAKER WITH MAGNETIC DEVICE RELEASABLE I TO EFFECT OPENING OFTHE BREAKER Original Filed 001;. 29, 1964 Sheet 5 of s June 17, 1969 D.JOHNSON 3,450,955

CIRCUIT BREAKER WITH MAGNETIC DEVICE 'RELEASABLE TO EFFECT OPENING OFTHE BREAKER Original Filed on. 29, 1964 Sheet 3 of 3 FIG. 7

- .0. H9 SOURCE H9 SOURCE FIG. 8.

United States Patent CIRCUIT BREAKER WITH MAGNETIC DEVICE RELEASABLE T0EFFECT OPENING OF THE BREAKER Floyd D. Johnson, Pittsburgh, Pa.,assignor to Westinghouse Electric Corporation, Pittsburgh, Pa., acorporation of Pennsylvania Continuation of application Ser. No.563,296, July 6, 1966, which is a continuation of application Ser. No.407,333, Oct. 29, 1964, which is a continuation-inpart of applicationSer. No. 103,635, Apr. 17, 1961. This application Mar. 24, 1967, Ser.No. 625,883

Int. Cl. H01h 47/04 US. 'Cl. 317-155.5 18 Claims ABSTRACT OF THEDISCLOSURE In electrical apparatus having a circuit breaker comprisingan electromagnetic latching device of a U-shaped structure, having apermanent magnet disposed between its legs, an armature releasably heldto the pole faces of the U-shaped structure and biased away from saidstructure and two magnetic circuits, one passing through the permanentmagnet and the armature to hold the armature to the U-shaped structurewhile the other passes through the permanent magnet and the base part ofthe U-shaped structure.

This application is a continuation of the parent application Ser. No.563,296, filed July 6, 1966, now abandoned, which was a continuation ofapplication Ser. No. 407,333, filed Oct. 29, 1964, now abandoned, whichwas a continuation-in-part of application Ser. No. 103,635, filed April17, 1961, now abandoned.

This invention relates generally to circuit breakers and moreparticularly to circuit breakers of the type having electromagnetictripping means.

An object of this invention is to provide an improved circuit breakerembodying a magnetic device operable to eifect opening of the circuitbreaker.

Another object of this invention is to provide a circuit breakerembodying an improved electromagnetic latching device releasable toeffect automatic opening of the circuit breaker.

Another object of this invention is to provide a circuit breaker withimproved means for effecting high speed tripping operations.

Other objects of this invention will be explained fully hereinafter orwill be apparent to those skilled in the art.

In accordance with one embodiment of the invention, a circuit breaker isprovided comprising an e1ectromagnetic latching device that embodies agenerally U-shaped structure of magnetic material such as soft iron,having a permanent magnet disposed between its legs. An armature isreleasably held to the pole faces of the U-shaped structure and isbiased .away from this structure. There are two separate magneticcircuits in the electromagnetic device. One of the magnetic circuitspasses through the permanent magnet and the armature. The mangetic fluxin this circuit works to hold the armature to the U-shaped structure.The other-magnetic circuit passes through the permanent magnet and thecross-over part or base part of the U-shaped structure. Two coils areprovided around one leg of the U-shaped structure on opposite sides ofthe permanent magnet. These coils are energized with direct current toreciprocate magnetic flux between the two magnetic circuits to cause thearmature to be alternately released from the U-shaped structure and heldto the U-shaped structure. When the armature is held to the U-shapedstructure, it latches the circuit breaker latch means in a latchingposition and when released it releases the latch means to effect atripping operation.

In another embodiment of the invention, a circuit breaker is providedcomprising an electromagnetic latching device that embodies a generallyH-shaped structure comprising two legs of magnetic material, such assoft iron, and a permanent magnet connecting the two legs. An armaturestructure is provided embodying two armatures disposed at opposite endsof the H-shaped magnetic structure. The armatures are connected in aspaced relationship by means of two side members to move as a unit. Thearmatures are so spaced that only one armature at a time can engage themagnetic structure. This electromagnetic device comprises twoalternately energized magnetic circuits. One of these magnetic circuitspasses through the permanent magnet and one of the armatures, and theother circuit passes through the permanent magnet and the otherarmature. Two coils are provided around one of the legs of the magneticstructure on opposite sides of the permanent magnet. These coils areenergized in a manner to effect reciprocation of magnetic flux betweenthe magnetic circuits to thereby effect reciprocation of the armaturestructure. Reciprocation of the armature structure effects latching andtripping of the circuit breaker in a manner to be specificallydescribed.

For a better understanding of the nature and objects of the invention,reference may be had to the following detailed description, taken inconjunction with the accompanying drawings, in which:

FIGURE 1 is a partly schematic elevational view of an electromagneticdevice;

FIG. 2 is a view, partly in section and partly in elevation, of aportion of a circuit breaker utilizing the electromagnetic device ofFIG. 1;

FIG. 3 is an elevational view of a modification of the electromagneticdevice shown in FIG. 1;

FIG. 4 is a view, partly in elevation and partly in section,illustrating the use of the electromagnetic device of FIG. 3 in thecircuit breaker shown in FIG. 2;

FIGS. 5A and 5B are graphs illustrating characteristics of theinvention;

FIG. 6 is a partial view illustrating a modified form of the circuitbreaker seen in FIG. 2;

FIG. 7 is a view similar to FIG. 6 and illustrating another modificationof the invention;

FIG. 8 is a partial view of a modified form of the invention disclosedin FIG. 4.

Referring to the drawings and particularly to FIG. 1, an electromagneticdevice 1 comprises a base 2 upon which is mounted a generally U-shapedstructure 3, an armature 5 engaging the U-shaped structure, two springs7 biasing the armature away from the U-shaped structure 3, and stopmembers 8 for limiting the upward movement of the armature. A lever 9,which is pivotally at tached to an arm 11 that is attached to thearmature 5, and which is pivotally supported by means of bracket 13, isprovided for resetting the armature after an opening operation.

The U-shaped structure 3 comprises two legs 15 of magnetic material,such as soft iron, having pole faces 17 at their free ends. The legs 15are connected by a base or cross-over part 19 of magnetic material suchas soft iron. A permanent magnet member 21 is supported by means ofbrackets 23 between the two legs 15. The coils 25 and 27 are providedaround one of the legs 15 on opposite sides of the permanent magnetmember 21.

The electromagnetic device 1 is shown in FIG. 1 in the closed position.There are two separate circuits of magnetic flux provided by thepermanent magnet 21 in the electromagnetic device 1. The first magneticcircuit extends from the pole N of the permanent magnet 21 through theupper part of one of the legs 15, the armature 5, the upper 3 part ofthe other leg -15 and back to the pole S of the permanent magnet 21. Thesecond magnetic circuit extends from the pole N of the permanent magnet21 through the lower part of one of the legs 15, the base or cross-overpart 19, the lower part of the other leg 15 and back to the pole S ofthe permanent magnet 21.

As can be seen in FIG. 1, the coils 25 and 27 are connected to asuitable source of direct current and are controlled by operation ofswitches S and S respectively, each of which switches may be a standardtype spring return push-button switch.

As will be hereinafter specifically described, when the parts are in theposition shown in FIG. 1, approximately 90% of the magnetic fluxemanating from the permanent magnet member 21 takes the path of thefirst circuit through the armature 5 working to hold the armature to theU-shapcd magnetic structure 3. The other 10% of the magnetic flux takesthe path of the second circuit through the cross-over part 19.

If the coil member 25 is momentarily energized, by operation of theswitch S to buck the magnetic flux in the first or upper circuit, thisflux will then shift to take the path of least reluctance through thesecond or lower circuit. This shift of magnetic flux will effect releaseof the armature 5 from the U-shaped structure 3 and the armature '5 willmove up under the bias of the springs 7 to engage the stop members 8.The armature 5 will then remain in this open position until an upwardforce (not shown) is applied to the outer end of the lever '9 to movethe armature 5 back to the closed position shown in FIG. 1. When thearmature 5 is in the closed position, the lower coil 27 can then bemomentarily energized, by operation of the switch S to buck the flux inthe second or lower magnetic circuit, in which case the flux will shiftto take the path of least reluctance through the first or upper magneticcircuit to again work to hold the armature 5 to the U-shaped magneticstructure 3.

With both coils 25, 27 then deenergized, the magnetic circuits areestablished with approximately 90% of the magnetic flux emanating fromthe permanent magnet 21 working in the first magnetic circuit and theremaining 10% of magnetic flux being in the second magneticcircuit.'This circuitry so established will be stable until the uppercoil 25 is again energized to buck the flux in the upper or, firstmagnetic circuit to effect another opening operation of theelectromagnetic device 1.

The memory action whereby the magnetic fiux remains largely in theportion of the magnetic circuit where it most recently has beenestablished can be explained by the magnetic properties of the parts, asrepresented typi-' cally in. the curves of FIGS. 5A and 5B. The softiron core has a hysteresis loop and the permanent magnet has a curve asshown of magnetomotive force (MMF) plotted against flux.

With the magnetic structure assembled, and with one or both coilsappropriately energized with direct current, the flux through onearmature or both, such as 5 of FIG. 1, will be raised from O of FIG. 5Aalong the dotted line to the maximum point B. At the same time the fluxin the cross-over part 19 of the magnet structure will carry littleflux, since with respect to this leg, the coil or coils will buck(rather than boost) the fiux efforts of the permanent magnet. When thecoil is de-energized, the flux in 5 of FIG. 1 will follow the curve frompoint B of FIG. 5A to some point such as A corresponding to a MMF of H,at which point equilibrium will exist between the permanent magnet andthe soft iron magnet structure. This equilibrium point for the permanentmagnet is at A of FIG. 5B.

It is now obvious that the magnetomotive force H available to establishflux in the second magnetic circuit through the cross-over part 19 issmall and will establish little flux, since it will be acting on acircuit having a magnetization curve such as -3 of FIG. A. On arepetitive cycling the coil energization would be expected 4 to reducethe flux in the inactive circuit to substantially zero, so that it wouldalways be given a fresh start.

Although the closing operation hereinbefore described was effected bymeans of applying a force to the free end of the lever 9, it can beunderstood that if the springs 7 are light enough, for certainapplications of the electromagnetic device 1, the resetting force andlever mechanism 9, 11, 13 can be omitted, in which case, when the coil27 is energized to buck the magnetic flux in the second or lowermagnetic circuit, the flux will take the path of least reluctancethrough the air gaps and armature 5 to attract the armature 5 to theU-shaped structure and pull the armature to the closed position withoutthe aid of any external mechanical resetting force.

As was specifically described, the coils 25 and 27 were alternatelyenergized to buck the magnetic flux or increase the reluctance in theirrespective circuits to effect a transfer of magnetic flux between thetwo magnetic circuits. It is to be noted that the coils 25 and 27 couldbe wound with a polarity such that the coil 27 would be energized toeffect a decrease of the reluctance in the second or lower magneticcircuit to effect a transfer of magnetic flux from the upper magneticcircuit to the lower magnetic circuit to effect release of the armature5, and such that the coil 25 would be energized to effect a decrease ofthe reluctance in the first or upper magnetic circuit to elfect atransfer of magnetic flux from the lower magnetic circuit to the uppermagnetic circuit to effect attachment of the armature 5 to the U-shapedstructure 3.

Another method of operation would be to connect and energize the coils25 and 27 simultaneously in such a manner that when the reluctance ofone of the magnetic circuits is increased, the reluctance of the othercircuit will be simultaneously decreased to effect a transfer ofmagnetic flux from the one to the other magnetic circuit. Transfer ofmagnetic flux back from the other to the one magnetic circuit would thenbe facilitated merely by reversing the direction of the flow of currentin the coils 25, 27.

The electromagnetic device 1 is shown in FIG. 2 embodied in a circuitbreaker 31 that comprises an operating mechanism 33 and a contactstructure 35. The circuit breaker 31 is of the type specificallydescribed in the patent to F. E. Florschutz et al., Patent No.2,647,182, assigned to the assignee of the instant application. Thecontact structure 35, which is illustrated diagrammatically, may be ofany conventional construction, either an oil-break, air-break or agas-blast type, and it is adapted to be operated to the open position bymeans of an accelerating spring 37. The circuit breaker 31 is operatedto the closed position by means of the operating mechanism 33 which, inthe embodiment shown, is of the compressed-fluid type.

The operating mechanism 33 includes an operating cylinder 39 which isclosed at its upper end by a plate 41 that is secured to the cylinder 39by means of bolts (not shown). An operating piston 43 is mounted in theop erating cylinder 39 and has secured thereto a piston rod 45 that isslidable through an air-tight opening in the plate 41. Rigidly securedto the upper end of the piston rod 45, is a coupling 47 that isreleasably connected to a coupling 49 by means of an inverted oroverlapping toggle comprising toggle links 53 and 55. The coupling 49 issecured to a breaker operating rod 56 in a suitable manner. Thebreaker'operating rod 56 is operatively connected to the circuit breakercontact structure 35 by means of a suitable linkage.

The toggle link 53 comprises a pair of spaced parallel links pivotallyconnected by means of a pivot pin 57, to the coupling 47. The togglelink 55 comprises a single link which is disposed between the links 53and which is pivotally connected by means of a pivot pin 59 to thecoupling 49. The toggle links 53 and 55 are pivotally connected,together by means of a knee pivot pin 61.

In order to provide a straight-line movement on the piston rod 45 andthe breaker operating rod 56, and to assist the trip-free toggle 53, 55in maintaining the breaker closed, the pivot pins 57 and 59 are providedwith rollers 63, there being a roller 63 mounted on each end of each ofthe pivot pins 57 and 59. These rollers cooperate with correspondingvertical slots 65 formed in a pair of spaced frame members 67 that arerigidly mounted on the plate 41 and that extend upwardly in a spacedparallel relation. In order to provide suitable hearing surfaces for therollers 63, plates 69 are provided with slots coinciding with the slots65 and are secured to the outside of each of the frame members 67 in anysuitable manner, preferably by welding.

The circuit breaker is held in the closed position by means of a mainlatch 71 and a light load latch mechanism indicated generally at 73. Themain latch 71 is pivotally mounted on a pin 75 which is supported in theframe members 67. The main latch 71 is biased by means of a springpressed plunger 77 into the latching position engaging a latchingsurface 79 on the coupling 47. The plunger 77 is slidably mounted in anopening in a cross bar 81 that is rigidly supported between the framemembers 67, and the plunger is biased by means of a compression spring83 that is compressed between the cross bar 81 and a washer 85 on theplunger. The main latch 71 is provided with a latching surface 87 forcooperating with the latching surface 79 on the coupling 47 and it alsohas a downwardly extending projection 89, the purpose of which will bedescribed later.

The light-load latching mechanism 73 includes an under-set trippingtoggle comprising toggle links 91 and 93, and a trigger latch 95operating to releasably maintain the tripping toggle in its under-setposition. The toggle link 91 comprises a pair of links rigidly joined bya cross member 97 which links are pivotally mounted on a fixed pivot pin99 supported by the frame members 67. At their free ends, the togglelinks 91 carry between them a latch roller 101 with which the triggerlatch 95 cooperates to maintain the tripping toggle 91, 93 in itsunderset position. The toggle link 93 comprises a pair of spacedparallel links disposed one on each side of the link 91 and pivoted onthe knee pivot pin 61 of the trip-free toggle 53, 55 outside of thetoggle links 53. The toggle links 93 are pivotally connected to thetoggle link 91 by means of a knee pivot pin -3.

The trigger latch 95 is pivotally mounted on a pivot pin 105 supportedin a pair of spaced brackets 107 (only one being shown) which in turnare rigidly secured to a cross plate 109 that is mounted on the framemember 67. The trigger latch 95 is biased to latching position by meansof a spring 111 disposed between the cross plate 109 and an extension113 of the latch 95. The latching position is determined by engagementof a tail portion 115 of the latch 95 with the cross plate 109. Thearmature 5 of the electromagnetic device 1 is connected to the triggerlatch 95 by means of a pivot pin 117. The electromagnetic device 1 issupported on a bracket 119 that is rigidly secured to the side plates 67The main latch 71 holds the piston 43 in the closed position shown inFIG. 2 against the force of two nested springs 121 that are compressedbetween the bottom of the piston 43 and the bottom of a downwardlyextending cylindrical portion 123 of the cylinder 39. The acceleratingspring 37 applies an upward force on the breaker operating rod 56. Sincethe pivot pins 57 and 59 are constrained by the slots 65 to move in astraight-line, a small component of this upward force is applied throughthe link 55 to the tripping toggle 91, 93. Since the tripping toggle 91,93 is only slightly underset, a very small component of the force of theaccelerating spring 37 is applied through the tripping toggle 91, 93biasing the link 91 in a counterclockwise direction about the pivot 99.This movement is restrained by the roll-off type engagement of the latchroller 101 with the trigger latch 95. The magnetic flux in the first orupper circuit of the electromagnetic device 1 cooperates with a spring111 to hold the armature 5, and the trigger latch to which the armatureis secured, in the closed latching position shown.

The coils 25 and 27 (FIG. 2) are connected to a suitable source of DCpower. The coil 25 is energized by a closing operation of the switch SPwhich switch may be a spring return manually operable push-buttonswitch. The coil 25 will also be energized upon the occurrence ofpredetermined overload current conditions in the circuit controlled bythe breaker, by automatic operation of the switch 8A to the closedposition. The switch SA can be closed automatically, for example, bymeans of a relay that is connected to be actuated upon the occurrence ofan overload current in the circuit that is to be controlled by thebreaker. The switch S is a limit switch that is operated to be closed bythe pin 59 when this pin reaches its fully open position (not shown) atthe top of the slot 49.

In the closed position shown in FIG. 2, the larger portion of magneticflux in the electromagnetic device 1 works in the upper magnetic circuitto hold the armature 5 in the closed position to thereby hold thetrigger latch 95 and the circuit breaker 31 in the closed position. Wheneither of the switches SA or SP is momentarily closed, the coil 25 ofthe electromagnetic device 1 is energized to buck the flux in the uppermagnetic circuit to transfer flux to the lower magnetic circuit toelfect release of the armature 5. Upon release of the armature 5, theforce of the opening spring 37, acting through the link 55 and trippingtoggle 91, 93, forces the roller 101 to move the latch 95counterclockwise out of latching position to release the tripping toggle91, 93. The force of the opening spring 37 causes the tripping toggle91, 93 to collapse moving the link 91 in a counterclockwise directionabout the pivot 99. As soon as the tripping toggle 91, 93 starts tocollapse, the breaker operating rod 56 starts to move upwardly to openthe contact structure 35. The hpward movement of the breaker operatingrod 56 and the collapse of the tripping toggle 91, 93, causes clockwiserotation of the trip-free toggle link 53. When the breaker rod 56 hastraveled upwardly a very short distance, approximately /z of an inch, atail portion 125 on the toggle link 53 engages the projection 89 on themain latch 71 and cams the main latch 71 to unlatching positionreleasing the piston rod 45, whereupon the powerful springs 121 thrustthe piston 43 and the piston rod 45 upwardly at a speed greater than theopening speed of the breaker operating rod 56. The piston rod 45 andoperating rod 56 are moved upwardly by the force of the springs 121 toopen the circuit breaker. Since the pivot pins 57 are constrained by theslot 65 to travel in a straight line and the speed of upward movement ofthe pin 57 is greater than the speed of upward movement of the pin 59,the toggle link 53 will cause the link 55 to rotate counterclockwiseabout the pivot pin 59 toward the inverted position of the toggle 53,55. This action through the pin 61 and link 93 rotates the link 91clock- -wise about its pivot 99 far enough to permit reengagement of thespring biased trigger latch 95 under the latch roller 101. This actionalso recouples the piston rod 45 to the breaker operating rod 56 and theparts thereafter travel in unison to the full open position of thebreaker moving the piston 43 to the top of the cylinder 39. When the pin59 reaches its fully open position at the top of the slot 49, itoperates to close the limit switch S This energizes the coil 27 to buckthe flux in the lower magnetic circuit to effect a transfer of flux tothe upper magnetic circuit, in the same manner previously described,whereupon the flux again works to hold the armature in the latchedposition.

The circuit breaker is closed by admitting compressed gas to theoperating cylinder 39 above the piston 43, by means not shown. Thisforces the piston 43 and the piston rod 45 downward drawing the link 53downward. Since the toggle link 91 of the tripping toggle 91, 93 is nowlatched, the link 93 pivots about its pivot pin 103 which acts as afixed pivot, thereby holding the toggle 53, 55 in thrust transmittingposition during the closing operation. The closing force applied to thelink 53 is, therefore, transmitted through the link 55 to move thebreaker operating rod 56 downward to close the breaker.

Referring to FIG. 3, there is shown therein an electromagnetic device141 comprising a guide member 145 supported on a base 143. An H-shapedmagnetic structure 147 comprises two magnetic legs 149 and a permanentmagnet member 151 supported between the two legs by means of brackets153. The brackets 153 are secured to an upwardly extending portion 155of the guide member 145 to there-by support the magnetic structure 147.An armature structure indicated generally at 157' comprises two magneticarmatures 159 and 161 supported on opposite sides of the H-shapedmagnetic structure 147 and rigidly held in a spaced relationship bymeans of two side members 163. Two coils 165 and 167 are disposed on oneleg 149 of the H-shaped magnetic structure 147 on opposite sides of thepermanent magnet member 151. The side members 163 of the armaturestructure 157 are of such a length that only one armature 159 or 161 canengage the H- shaped magnetic structure 147 at a time.

In the position shown in FIG. 3, about 95% of the magnetic fluxemanating from the permanent magnet member 151 works in a first or uppermagnetic circuit passing from the permanent magnet 151 through the upperportion of one of the legs 149, the upper armature 159, the upperportion of the other leg 149, and back through the permanent magnet 151to hold the armature 159 to the magnetic structure 147. The remainingapproximately of the magnetic flux emanating from the permanent magnetmember 151 passes through the magnetic member 151, through the lower endof one of the legs 149, an air gap between the said lower leg and thearmature 161, the armature 161, an air gap between the armature 161 andthe other leg 149, the lower end of the other leg 149 and back throughthe permanent magnetic member 151.

When it is desired to operate the electromagnetic device 141, the coil165 is momentarily energized, by operation of a spring returnpush-button switch S to buck the magnetic flux in the first or uppermagnetic circuit whereupon this flux takes the path of least reluctancethrough the second or lower magnetic circuit drawing the armature 161and therefore the armature structure 157 upwardly as seen in FIG. 3 to aposition in which the armature 161 engages the H-shaped magneticstructure 147. After energization of the coil 165, approximately 95 ofthe magnetic flux emanating from the permanent magnet member 151 willwork through the second or lower magnetic circuit to hold the armaturestructure 157 in the upper position, and the remaining approximately 5%of magnetic flux will flow through the first or upper magnetic circuitwhich, at this time, comprises two air gaps between the upper ends ofthe legs 149 and the upper armature 159. When it is desired then toeffect a return of the armature structure 157 to the position in whichit is shown, the lower coil 167 is energized, by operation of a springreturn push-button switch S to buck the flux in the second or lowermagnetic circuit whereupon the magnetic flux returns to the upper orfirst magnetic circuit to again attract the armature 159 and thereforethe armature structure 157 back to the position in which it is shown.

It can be understood that the electromagnetic device 141 is a memorydevice in that the armature structure 157 will remain in the position towhich it is moved upon momentary energization of the proper coil 165 or167. The electromagnetic device 141 can be used for a number of specificapplications. For example, it could be usedas a two position relayoperable by momentary coil energization with positive mechanical loadingin each direction. Another use of the electromagnetic device 141 wouldbe as a vibration relay or contactor operated by means of energizing thecoils 165 and 167 with an alternating current voltage.

The electromagnetic device 141 is shown in FIG. 4 as a magnetic latchingdevice for a circuit breaker of the type shown in FIG. 2. In this case,the armature structure 157 is attached to the trigger latch by means ofthe pivot pin 117. The device 141 is shown in the latched or closedcircuit position. In order to effect an opening operation, the uppercoil 165 is energized, by operation of either of the switches SA or SPto buck the magnetic flux in the first or upper magnetic circuit toeffect upward movement of the armature structure 157 to move the triggerlatch 95 in a counterclockwise direction about the pivot pin to effectan opening operation of the circuit breaker in the same mannerpreviously described. The armature structure 157 and the trigger latch105 are reset when the pin 59 (FIG. 2) reaches its fully open position,at the top of the slot 65, to engage and operate the limit switch SOperation of the limit switch S energizes the coil 167 to move thearmature structure back to the latched position. The circuit breaker canthen be closed in the same manner hereinbefore described.

As was described in relation to the electromagnetic device 1, the coils164 and 167 of the electromagnetic device 141 can be energizedalternately to either buck the magnetic flux in their associatedcircuits, or to magnetize their associated circuits; or they may beconnected in series or in parallel and energized so that when one of thecoils magnetizes its associated circuit, the other coil will buck themagnetic flux in its associated circuit to thereby effect a morepositive transfer of flux between the magnetic circuits.

Different modifications of the invention are disclosed in FIGS. 6, 7 and8. -In each of these figures, only the circuit breaker latch means isshown, it being understood that the other parts of the circuit breaker,in each case, are the same as those parts that were hereinbeforedescribed with reference to FIG. 2. In FIGS. 6 and 7, those parts thatare thesame as parts previously described with reference to FIG. 2 areidentified by the same reference characters used in FIG. 2. In FIG. 8,those parts that are the same as parts previously described withreference to FIG. 4 are identified by the same reference characters usedin FIG. 4.

Referring to FIG. 6, when the switches S and 8,, are

both closed, the coil 27 is energized to increase the reluctance in thelower magnetic circuit to thereby effect a transfer of magnetic fluxfrom the lower magnetic circuit to the upper magnetic circuit in thesame manner hereinbefore described. This transfer of magnetic fluxoperates to secure the armature 5 and the latch 95 in the latchingposition. The switch S is a limit switch that is engaged andautomatically operated to the closed position when the pin 59 (FIG. 2)reaches the top of the slot 65. The

switch S is a limit switch that is engaged and automatically operated tothe closed position when the latch 95 reaches the latching positiondisclosed in FIG. 2. When the latch 95 reaches the latching positiondisclosed in FIG. 2, the armature 5, which is pivotally secured to thelatch 95 by means of the pin 117, engages the pole faces of the U-shapedmagnetic structure 3. The switch S is provided to protect against thepossibility of having a momentary energization of the coil 27 at a timebefore the armature 5 in the latching position. With the provision ofthe switches S and S in electrical series, the coil 27 will be energizedto increase the reluctance in the lower magnetic circuit only when thecircuit breaker is open and only when the armature 5 and latch 95 are inthe latching position. Thus, energization of the coil 27, even if it isa momentary energization during a rapid successive opening and closingoperation of the breaker, will operate to effect a transfer of magneticflux to the reset armature 5 to latch the armature 5 and latch 95 in thelatching position to thereby prepare the circuit breaker for a closingoperation in the same manner as was hereinbefore described.

Since the pin 59 will be at the upper end of the slot 65 while thecircuit breaker is maintained in the opened position, and because thelatch 95 will reach the latching position disclosed in FIG. 2 when thecircuit breaker is in the opened position, the coil 27 will becontinuously energized during the time that the circuit breaker is open.If it is desired to provide means for preventing continuous energizationof the coil 27, while the circuit breaker is open, a relay 181 (FIG. 7)may be provided to cut off the flow of current through the coil 27.Referring to FIG. 7, the relay 181 comprises a contact structure 183, acoil 185, a coil 186 and a dashpot 189. When the circuit breaker isclosed, the relay is in the normally closed position seen in FIG. 7.When the switches S and 8;, are closed in the same manner hereinbeforedescribed to effect energization of the coil 27, the relay coil 187 isenergized to operate the relay contacts 183 to the open position therebybreaking the circuit through the coil 27. In the structure disclosed inFIG. 7, the relay coil 187, rather than the coil 27, is continuouslyenergized when the circuit breaker is closed, the relay is in thenormally 189 is provided to delay opening of the relay contacts 183after the coil 187 has been energized to thereby provide that the coil27 will be adequately energized to effeet a shift of magnetic flux backup through the armature when the latch 95 is in the latching position.With the armatureS and the latch 95 in the latching position disclosedin FIG. 2, the circuit :breaker can be operated to the closed positionin the same manner as was hereinbefore described.

Referring to FIG. 8, there is disclosed therein the latching device ofFIG. 4 and a normally open limit switch S that is engaged and operatedto the closed position automatically when the pin 59 reaches the upperend of the slot 65. The relay 181 is the same relay that was describedwith reference to FIG. 7. The relay 181 is operated in the same manneras was hereinbefore described to break the circuit through the coil 167thereby providing that the relay coil 187 rather than the latching coil167, will be continuously energized when the circuit breaker is in theopen position.

In each of the circuit breakers disclosed in FIGS. 2, 4, 6, 7 and 8, themagnetic latch and coil arrangement could be adapted to effect atransfer of magnetic flux by either increasing the reluctance in themagnetic circuit from which the flux is to be transferred or decreasingthe reluctance in the magnetic circuit to which the flux is to betransferred. As was hereinbefore set forth with regard to the structuresdisclosed in FIGS. 1 and 3, it may be desirable in some applications tosimultaneously increase the reluctance in one magnetic circuit anddecrease the reluctance in the other magnetic circuit to effect atransfer of flux from the one to the other magnetic circuit.

From the foregoing, it can be understood that there is provided by thisinvention an improved circuit breaker comprising a magnetic latch thatcan be released quickly with a minimum of energy input into the coils.In view of this fast latch release, the circuit breakers of thisinvention are particularly useful in situations where highspeed openingof the contacts is required.

While the invention has been disclosed in accordance with theprovisionsof the patent statutes, it is to be understood that variouschanges in the structural details and arrangement of parts thereof maybe made Without departing from some of the essential features of theinvention.

I claim as my invention:

1. A circuit breaker comprising a stationary contact, a movable contactcooperable with said stationary contact, an operating mechanismreleasable to effect opening of said contacts, a latching mechanismreleasable to release said operating mechanism, tripping meanscomprising a magnetic device, said magnetic device comprising a magneticstructure comprising two generally parallel pole pieces, each of saidpole pieces having a pole face at a first end of said magneticstructure, said magnetic structure comprising a cross-over partconnecting said pole pieces, flux-supplying means positioned betweensaid pole pieces in a position between said pole faces and saidcross-over part, an armature in a latching position attracted to saidpole faces, said armature upon release thereof moving away from saidpole faces to release said latching mechanism, said magnetic devicecomprising a first magnetic circuit and a second magnetic circuit, saidflux-supplying means supplying the magnetic flux for said first andsecond magnetic circuits, the magnetic flux in said first magneticcircuit working to maintain said armature in said latching position, andmeans for transferring magnetic flux from the first to the secondmagnetic circuit to release said armature to thereby effect opening ofsaid contacts.

'2. A circuit breaker according to claim 1, said first magnetic circuitcomprising said armature, said second magnetic circuit comprising saidcross-over part, and said means for transferring magnetic flux from saidfirst to said second magnetic circuit comprising electrical input means.

3. A circuit breaker according to claim 2, and means operable to resetsaid armature in said latching position and to return magnetic flux tosaid first magnetic circuit whereupon said first magnetic circuit worksto maintain said armature in said latching position, and means operablewhen said armature is maintained in said latching position to close saidcontacts.

4. A circuit breaker according to claim 1, and said flux supplying meanscomprising a permanent magnet member.

5. A circuit breaker according to claim 3, and said gux supply meanscomprising a permanent magnet mem- 6. A circuit breaker according toclaim 1, said magnetic structure comprising a generally U-shapedmagnetic structure with said pole pieces being the legs and with saidcross-over part being the bight portion of said generally -shapedmagnetic structure, and said flux-supplying means comprising a permanentmagnet member.

7. A circuit breaker according to claim 3, and said means operable toreset said armature and return magnetic flux to said first magneticcircuit cmprising another electrical input means.

8. A circuit breaker according to claim 7, said magnetic structurecomprising a generally U-shaped magnetic structure with said pole piecesbeing the legs and with said crss-over part being the bight portion ofsaid generally -shaped magnetic structure, and said flux-supplying meanscomprising a permanent magnet member.

'9. A circuit breaker comprising, in combination, a stationary contact,a movable contact coopera-ble with the stationary contact to open andclose the breaker, releasable latching means latching the circuitbreaker in the closed position, tripping means comprising a magneticstructure, an armature releasably attached to the magnetic structure andreleasable therefrom to effect release of the latching means to therebyeffect opening of the circuit breaker, a first magnetic circuit passingthrough the armature to hold the armature to the magnetic structure, asecond magnetic circuit separate from the armature, a first electricalinput operable to effect a transfer of magnetic flux from the firstmagnetic circuit to the second magnetic circuit to effect release of thearmature to thereby effect opening of the circuit breaker, means forresetting the armature and relatching said latching means, a secondelectrical input operable only after said armature is reset and saidlatching means is relatched to effect a transfer of magnetic flux fromthe second magnetic circuit to the first magnetic circuit to return theelectromagnetic tripping means to the state in which the flux in thefirst magnetic circuit operates to hold the armature to the magneticstructure, and means for closing said circuit breaker whereupon saidarmature maintains said latching means in the latching position tothereby maintain said circuit breaker in the closed position.

10. A circuit breaker according to claim 9, said magnetic structurecomprising a generally U-shaped structure comprising two leg parts and across-over part, flux-supplying means extending between the leg partsand positioned between the cross-over part and the free ends of the legparts, said armature being releasably attached to said U-shaped magneticstructure at the free ends of the leg parts ofthe U-shaped magneticstructure, said first magnetic circuit being independent of saidcross-over part and passing through said armature and through saidflux-sup plying means, said second magnetic circuit being independentof. said armature and passing through said cross-over part and throughsaid flux supplying means, and said flux supplying means comprising apermanent magnet member.

11. A;circuit breaker according to claim 10, and switch means operatingautomatically when said latching means is relatched to effect operationof said second electrical input.

12. A circuit breaker comprising, in combination, a stationary contact,a movable contact cooperable with the stationary contact to open andclose the breaker, an opeerating mechanism releasable to effect openingof said contacts, a latching mechanism releasable to release saidoperating mechanism, a magnetic trip device comprising a magneticstructure having first pole face means at one end thereof and secondpole face means at the other end thereof, an armature structurecomprisinga first armature opposite said first pole face means and asecond armature opposite said second pole face means, said armaturestructure comprising connecting means connecting said first and secondarmatures in a spaced relationship for unitary movement, and electricalinput means operable to effect movement of said armature structure torelease said latching mechanism to thereby effect opening of the circuitbreaker.

13. A circuit breaker according to claim 12, said connecting meansconnecting said first and second armatures in a spaced relationship suchthat only one armature at a time can be in an attracted positionattracted to the associated pole face means, said electrical input meansbeing operable to effect movement, of said armature structure back andforth to effect alternate positioning of said first armature againstsaid first pole face means and said second armature against said secondpole face means, and the movementin one direction of said armaturestructure effecting release of said latching mechanism.

14. A circuit breaker according to claim 12, said circuit breaker beingclosed and said first armature being in an attracted position in closeproximity to said first pole face means to position said armaturestructure in a first position to releasably latch said latching means inlatching position, said electrical input means upon momentaryenergization thereof effecting movement of said armature structure to asecond position wherein said first armature is positioned out of saidclose proximity with said first pole face means and wherein said secondarmature is positioned in an attracted position in close proximity tosaid second pole face means to thereby effect release of said latchingmechanism, and means operating upon release of said latching mechanismto effect opening of said contacts.

15. A circuit'breaker according to claim 14, and said magnetic structurecomprising a generally H-shaped structure comprising two legs ofmagnetic material and a permanent magnet flux supplying member disposedbetween said legs, each of said legs having a pole face at each of itsopposite ends, said first pole face means comprising the pole faces atone end of said H-shaped structure and said second pole face meanscomprising the pole faces at the other end of said H-shaped structure.

16. A circuit breaker according to claim 12, said magnetic structurecomprising a generally H-shaped structure comprising two legs ofmagnetic material and a permanent magnet flux supplying member disposedbetween said legs, each of said legs having a pole face at each of itsopposite ends, said first pole face means comprising the pole faces atone end of said H-shaped structure and said second pole face meanscomprising the pole faces at the other end of said H-shaped structure,said circuit breaker being closed and said first armature being in anattracted position in close proximity to said first pole face means toposition said armature structure in a first position releasably latchingsaid'latching mechanism, the flux generated by said permanent magnetworking through said first armature to maintain said armature structurein said first position, and upon momentary energization of saidelectrical input means said armature structure moving to move said firstarmature out of close proximity to said first pole face means and tomove said second armature into close proximity to said second pole facemeans thereby moving said armature structure to a position releasingsaid latching mechanism to thereby release said operating mechanism tothereby effect opening of said circuit breaker, and means for returningsaid armature structure to said first position and closing said circuitbreaker.

17. A circuit breaker comprising a stationary contact, a movable contactcooperable with said stationary contact, an operating mechanismreleasable to effect opening of said contacts, a roll-off type latchingmechanism releasable to release said operating mechanism, and adoublemagnetic-circuit magnetic device latching said latching mechanismand operable to release said latching mechanism.

18. A circuit breaker comprising a pair of cooperable contacts, anoperating mechanism releasable to effect opening of said contacts, alatching mechanism in a latching position releasable to release saidoperating mechanism, a magnetic device comprising a permanent magnetproviding magnetic flux to restrain said latching mechanism in saidlatching position, and said magnetic flux being transferable in saidmagnetic device to effect release of said latching mechanism.

References Cited UNITED STATES PATENTS 751,442 2/ 1904 Andrews 317-43 X1,042,183 11/1912 Woodbridge 33584 1,930,950 10/1933 Dalfell 317-1555 X2,056,147 9/1936 Hitchcock 3 17150 2,343,861 3/1944 Biggle 317l2,587,983 3/1952 Durand 317172 2,739,572 3/1956 Page 317--123 X2,794,881 6/1957 Frank 33524 X 2,888,290 5/1959 Pierce 317171 X3,022,450 2/ 1962- Chase 317123 X 3,023,285 2/1962 Favre 335-243,146,381 8/1964 Moreau 335237 X 3,165,723 1/1965 Radus 340174 3,228,0131/1966 Olson et al 340-474 JOHN F. COUCH, Primary Examiner.

R. V. LUPO, Assistant Examiner.

US. 01. X.R. 317 171, 181

